diff options
Diffstat (limited to 'net/ipv4')
| -rw-r--r-- | net/ipv4/ip_sockglue.c | 6 | ||||
| -rw-r--r-- | net/ipv4/tcp_ipv4.c | 20 |
2 files changed, 18 insertions, 8 deletions
diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c index d5487c858067..38d29b175ca6 100644 --- a/net/ipv4/ip_sockglue.c +++ b/net/ipv4/ip_sockglue.c @@ -886,6 +886,8 @@ static int compat_ip_mcast_join_leave(struct sock *sk, int optname, return ip_mc_leave_group(sk, &mreq); } +DEFINE_STATIC_KEY_FALSE(ip4_min_ttl); + static int do_ip_setsockopt(struct sock *sk, int level, int optname, sockptr_t optval, unsigned int optlen) { @@ -1352,6 +1354,10 @@ static int do_ip_setsockopt(struct sock *sk, int level, int optname, goto e_inval; if (val < 0 || val > 255) goto e_inval; + + if (val) + static_branch_enable(&ip4_min_ttl); + /* tcp_v4_err() and tcp_v4_rcv() might read min_ttl * while we are changint it. */ diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index a9cbc8e6b796..13d868c43284 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -508,10 +508,12 @@ int tcp_v4_err(struct sk_buff *skb, u32 info) if (sk->sk_state == TCP_CLOSE) goto out; - /* min_ttl can be changed concurrently from do_ip_setsockopt() */ - if (unlikely(iph->ttl < READ_ONCE(inet_sk(sk)->min_ttl))) { - __NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP); - goto out; + if (static_branch_unlikely(&ip4_min_ttl)) { + /* min_ttl can be changed concurrently from do_ip_setsockopt() */ + if (unlikely(iph->ttl < READ_ONCE(inet_sk(sk)->min_ttl))) { + __NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP); + goto out; + } } tp = tcp_sk(sk); @@ -2070,10 +2072,12 @@ process: } } - /* min_ttl can be changed concurrently from do_ip_setsockopt() */ - if (unlikely(iph->ttl < READ_ONCE(inet_sk(sk)->min_ttl))) { - __NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP); - goto discard_and_relse; + if (static_branch_unlikely(&ip4_min_ttl)) { + /* min_ttl can be changed concurrently from do_ip_setsockopt() */ + if (unlikely(iph->ttl < READ_ONCE(inet_sk(sk)->min_ttl))) { + __NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP); + goto discard_and_relse; + } } if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb)) |